Pixels per inch for web
Posted by René | Filed under Photoshop, introduction, software, web
What is the significance?
Simply put? Nothing.
Well, if that were all I had to say on the subject, this would have to be my shortest blogpost ever… Okay, a bit more info then:
A lot of first time DSLR users are concerned that their shiny new camera delivers files that are “only” 72dpi, while their old point and shoot delivered 300dpi files. Why is this concern unwarranted? Surely 300 is more then 72, and more is better, right?
Wrong
The old wisdom saying is that “300dpi is for printing and 72dpi is for screen”.
There are a few things wrong with that.
First and foremost, the term “dpi” stands for dots per inch. In a digital file there are no dots, only pixels. So the correct term is pixels per inch (ppi).
Also, 72ppi originated as it was the resolution of an ancient Mac monitor. Current monitors have a much higher pixel density: My old 12″ PowerbookG4 for instance has a screen resolution of about 100ppi. Most current screens are somewhere between 80 and 120ppi.
Do the math…
for your screen: Simply measure width and height and divide the number of pixels by the measured values… Tip: Once you found the figure for your screen, be sure to enter it in the PSCS4 preferences under “Units and Rulers, Screen resolution”: That way, the “Zoom, Print size” will show an accurate sized preview.
So, is a 300ppi file better then a 72ppi file?
No difference
If you hadn’t gathered as much from the above, for display on screen, only the display you’re using will determine the “resolution”.
So, a file that contains for instance 500×750 pixels will be displayed at a different size (in inches, centimeters, or whatever you prefer), depending on the screen you’re using to view it. The arbitrary ppi figure set in the file has no relevance whatsoever.
To illustrate that, here is an example: Each file is 500×750 pixels. One is 72ppi, the other 300ppi.
Notice the difference? No? That’s because there isn’t any.
Why use it then?
Because you have to put something in the box: There is no way that Photoshop will allow you to not fill in a value. However, what you put in there is pretty arbitrary. Use whatever you like basically for display on screen.
I prefer to use 300ppi for general use, since then the “image size” dialog box will quickly tell me about how large I can print an image at decent quality. For web, I mostly use 72ppi (unless I forget) since, well, that’s what some people expect…
Some more reading: here
Tags: browser, dpi, PhotoshopCS4, ppi, Save for web, web
Photoshop CS4 Color Settings
Posted by René | Filed under Color Management, Photoshop, introduction, software
Once, and for all
Never thought I’d blog about something as individual as PS Color Settings… Then again, there is so much conflicting, incomplete or downright inaccurate info on the web, I thought it might be time to set the record straight.
Individual
First of: Like more things in photography life there is no “Magic Bullet”. If that’s what you are looking for, better get used to this idea: You need a basic understanding of Color Management.
On the bright side: The settings in the Color Settings dialog box affect a number of things. However, unless done totally wrong, how your images are displayed is not one of those things.
Settings nobody should use
There is no “Magic Bullet”, but there is a “one size fits no-one”: The setting called “Monitor Color”.
What does it do? Let’s go through the main problems step by step:
It sets your monitor profile as default working space. So every time you calibrate your monitor (you do that regularly, right?) your default working space changes. And your default working space is limited to your monitors gamut. Not good if you are on a laptop for instance.
One additional problem is that equal values for R, G and B might not give a neutral gray. And there are other problems.
One of those problems is, that it sets all color management policies to “off”. Note that, contrary to popular belief, setting “monitor profile” does not turn off color management altogether: The one good thing in all this mess is that you are presented with this dialogue box when opening an image with an embedded profile:
Damage
The damage you can do here is very real:
If you tick the top option (“Use the embedded profile”), no damage is done. The image will be shown correct, and all data is retained. Not bad at all.
If you pick option #2 (“Convert to working space”), irreversible damage is done: The pixels in the image will be converted (changed!) to your monitor profile. Color numbers are converted (so colors will display correctly), but all colors out of your monitors gamut will be clipped. Poof! Gone. Forever.
If you pick option #3 (“Discard the embedded profile”), at least you won’t be damaging the file on import as in option #2 (it’s reversible by assigning the correct profile). But you will not be seeing the image correctly. So any “color correction” you do will be incorrect. The fact that the color numbers aren’t changed is a moot point because of this: What you see definitely will not be what others see.
Other problems
Yet another problem is that, even if you use embedded profiles, you will get no warning when you copy-paste an image into a new document (which by default will not have an embedded profile), or into an image with a different working space: The colors will change. See option #3 above.
So, I see no reason for anyone to use it. Not even web designers. Yes, I know that lots of browsers are not color managed. However, there are not lots of people using your screen, are there?
The only reason to temporarily set it, is when you need to check whether Photoshop is using the correct monitor profile.
Better
Just about any of the other “presets” is better. These presets are grouped in a few categories. When you scroll trough them, you might notice a few things:
There are settings for Europe and North America. And in every region there are 3 settings: for “General Purpose”, “Prepress” and “Web/Internet”. When you tick “more options” Japan appears, which has the same trio but adds “Color For Newspaper” and “Japan Magazine Advertisement Color”. There also appear a few other “international” presets.
Rather then going into each one in depth, I’ll generally explain some differences and possible pitfalls: They are “presets”, but IMO none is perfect. You can use them as a starting point however.
I start of with “more options” unchecked. And the screenshots are for the European presets. However, the comments I give are the same for the other localisations.
General Purpose
It Isn’t. It’s really that simple. Like I said: There’s no magic bullet.
Main drawback is that you get no warning whatsoever for profile mismatches: When you open two images in a different working space, and paste one into the other, colors will be converted. Which, as said, is irreversible and might give irreversible damage. If I’m going to damage my image, I damn well want to be notified.
Prepress
Is quite a decent choice if you are doing prepress work. Profiles are preserved, you are warned when you get a mismatch, and reasonable profiles are chosen for CMYK, gray and spot. (depending on the area you chose, CMYK and dot gain are different.) Then again, if you are doing prepress work, I’d hope that you know enough about color management that you don’t need to read my thoughts on it…
Web/Internet
This is the only preset where converting to working space might make sense in my opinion: If you are just doing work for internet, anything should be sRGB. If you have to ask why: Read my blogpost on the subject. Then again, I’d like a warning if an image has no embedded profile: In some cases it might be because someone screwed up. This is largely a personal preference however.
Other presets
Are “more of the same” (two other Japanese presets only differ in CMYK, gray and spot from Japan Prepress2). The “Phase One” workflow is the odd one out: It sets a gray profile of Gray Gamma 2.2 which is quite sensible. Then again, the CMYK profile is “Euro-Catalog”, which I never need.
The other options (Colorsync (mac only), PS5) are obsolete legacy.
Create your own
Since everybody’s needs are different, it makes sense to make your own preset then, doesn’t it? Sure! But you need to know what each setting does. Some things are pretty straight forward, others not so much.
Default working spaces: RGB
Pretty much up to personal preference. The question “what RGB color space is best” I’ll leave be for now. Use whatever working space you use in your raw converter of choice. Two points I do want to make: If you don’t understand color management, do yourself a favor and use sRGB as a working space everywhere. On the other hand, if you are using a wide gamut color space (anything larger then AdobeRGB) do so in 16 bit per channel only!
Settings never to use are AppleRGB, ColorMatchRGB or GenericRGB. These are based on monitors that went the way of the dodo…
CMYK and others
For CMYK working space: Most people won’t ever print something on an offset press, so won’t ever be needing CMYK. When you do need it, make sure the printer tells you what profile to use, and set that as the default: It has some impact further down the road in PSCS4.
Don’t ever use GenericCMYK or one of the “old” Photoshop CMYK settings here: No good reason to. When in doubt, you probably won’t ever need it, so pick the “default” for your region.
Same goes for Gray and Spot working space. If you do a lot of grayscale images for web, gamma 2.2 is the best setting. If you print them to a specific Offsetpress and you know what dot gain to use, by all means do. But in that case you probably wouldn’t be reading this article… For same reasons as above never, ever use Gamma 1.8. It’s obsolete.
Policies and Notifications
Choose “Preserve Embedded Profiles”, unless as explained above, you are a web designer and have thought about the subject a bit.
I don’t see the need to tick the “Profile mismatch: Ask when opening” box, since I edit images from a known source, and the embedded profiles are what they are for a reason. So YMMV. I do tick the “Ask when pasting” and “missing profiles” boxes. The first because I want to be notified if an image profile is converted, the second because if there is no profile embedded, someone screwed up.
Note that if you choose “Discard the embedded profile (do not color manage)” here, the image will be shown as if it had the default working space embedded. This has the same effect as assigning your default working space: The image won’t display accurate, but it is reversible (by assigning the proper profile).
Another note (a big one) is that PS somehow doesn’t display this warning when pasting an image without profile into a document with an embedded color space! Colors will change.
Advanced: Conversion options
Engine: Leave at “Adobe (ACE)”. It’s the best choice, and if you have a specific reason why you would want to use another, you would not need my advice.
Rendering intent: Either perceptual or relative colorimetric for photographic images. Which is best will depend on the image. Not that this setting matters much: This is the rendering intent used by default when you go Image > Convert to profile (where you can change it in the dialog box) and it is used when going Image > Mode > CMYK for instance (which I would strongly advise against, since it offers no preview and no direct control)
The description says it all:
Always tick “Use Black point compensation” and also “Use Dither”: It makes banding or posterization much less likely.
The last option “Compensate for Screen -referred profiles” is only important if you make documents for Adobe After Effects. In that case: Tick it. Otherwise: Tick it as well, since it won’t matter then.
Advanced, but not to be used
“Desaturate Monitor Colors By” and “Blend RGB Colors Using Gamma”: Easy: Don’t tick those. They are not meant for photographers. Again: Read the description:
Possible pitfalls
As already mentioned, the settings set in the “Conversion options” will be used when changing from one color space to the next by going Image > Mode. So do not go there. Use Edit > Convert to profile instead. Yes you can also use it to convert from RGB to CMYK…
Another, less well known fact, is that the default profile is what determines the values in the info palette (Color picker) for anything but the color space the image is in. So if you use a CMYK or grayscale color picker on an RGB image, the readout will be for your current default CMYK or gray working space!
Another of the stupid less-then-brilliant decisions on Adobes part was to have the Select > Color Range > Out of Gamut selection be based on the default CMYK working space. Makes no sense whatsoever and makes the tool all but unusable for anyone who prints at home, but there it is…
Here is an sRGB image, softproofed for my Epson R2880, using glossy paper. The Gamut warning is on and shows no out of gamut colors. Notice the selection?
Conclusion
After reading this, you should know enough about the subject to create your own settings. After you did, save them as your own preset. It might also be a good idea to add a description.
Here’s mine:
Tags: Color Management, PhotoshopCS4, WYSIWYG
Canon DPP or Adobe Lightroom?
Posted by René | Filed under DPP, LightRoom, Problems, software
Or: Why I shoot Raw
I shoot a lot of Performing Arts. That often involves “difficult” lighting: Different light sources, with different color temperatures. And to make matters worse, they are fitted with colored gels most of the time.
While I mostly try to go for “pleasing color”, rather then “neutral skintone” (the lighting was done a specific color for a reason I think), this still poses some challenges every now and then.
Simply setting ‘tungsten’ white balance is an okay starting point, but with certain types or colors of lighting, I need to do quite a bit of tweaking to get the image where I want it.
For that reason, I choose to shoot Raw: Gives me the most flexibility, and allows me to change whitebalance without causing too much harm.
Raw converters
Most of the time, I use Lightroom 2 for editing these images: I prefer the workflow over using the combination of DPP and Photoshop: I can do local edits on the Raw file in LR, and I can save the DNG with all edits included. With DPP/PS, I have to save a layered psd file of each image (which might be about 100Mb or so. With hundreds of images, that eats up HDD space rather fast).
This might not make sense to everybody, but makes sense to me.
DPP offers better noise reduction and sharpening in my opinion, but most of the time LightRoom is good enough for the intended purpose (images for the web).
Sometimes not
Occasionally however, I come across an image that simply will not give decent results in LightRoom. Blue gelled lights often give problems: For one: No way to reduce noise without obliterating all detail on the process. A while back I processed one of those images.
Here’s what it looked like in LightRoom at my default settings (Camera Neutral):
Not the best rendering. Obviously, the purple causes some problems by “blocking up”, and the blue does horrid things as well: Details and sharpness are gone. (notice the faces? A bit further down are the images up close.)
One thing that might help some colors (but not blues in my experience) is switching the camera profile. In this case, “Adobe Standard” didn’t exactly help, and the ACR4.4 profile was so bad I won’t even bother posting the screenshot…
Adjusting white balance and using specific HSL adjustments helped the image quite a bit, but still, the details in the shadow stayed absent.
Time to try a different Raw converter…
DPP
Canon’s own DPP is a very different piece of software then LightRoom: It has no DAM capabilities, and only offers global adjustments. So any local editing must be done in Photoshop. For instance by doing multiple conversions and use masks in PS.
Also, the user interface is very different and seems to be a case of “you love it or you hate it”.
Most importantly however, it rendered this image quite different from LightRoom
DPP “As shot” looks quite “neon”, but it clearly contains more detail:
The lack of detail in LR is not caused by noise reduction: If NR in LR is set to 0, the difference is still apparent. Setting Color NR higher then about 7 does obliterate any detail that was left however. Clearly, LR Color NR is not just targeting color noise… Luminance NR doesn’t help the image, but doesn’t destroy it either.
In comparison, DPP does much different: you can set a fairly high amount of Chroma NR before you start losing detail, and it actually removes color noise. However, setting a Luminance NR of something as low as 2 visibly removes detail: Avoid this like the plague.
Finishing up
Setting a higher color temperature, different color tone, and using “tune” to shift the image toward green/yellowish helps colors in DPP, although some transitions in the beams of light still look quite harsh. LightRoom does better in that respect.
The most striking difference (apart from the loss of detail in LR) is that the smoke appears to be almost gone in DPP!
Sometimes neither works alone
So, this appears to be a case were neither Raw converter gives satisfactory results… DPP gives detail, but no smoke. LightRoom gives smoke, better transitions, yet no detail. RIT handles the image like DPP does, apart from the fact that is seems to do some noise reduction by default, with no (working) option to turn it off. So no sense in going that route: RIT is a bit more constricting then DPP (you can only adjust what you could adjust on the camera) and the user interface is horrid.
I finally decided to open both the LR and DPP conversion in Photoshop, and blend them together, thus getting an image that contained both detail and smoke:
If anyone wants to give this image a try, the Raw file can be downloaded from here.
Please respect my copyright, and only use the image for evaluation purposes.
Tags: DPP, LightRoom, software
Tethered shooting with a Canon camera
Posted by René | Filed under DPP, General, LightRoom, software, tether
Why should you?
If you are shooting portraits or architecture, it can be very useful to be able to view the images on a larger screen then that on the back of your camera: You can better judge focus, expression, exposure and composition for instance. Not only because the screen is bigger and of better quality (not to mention calibrated!), but also because the software you use might have some visual aids (clipping warning, grid, 100% view, stuff like that)
What do you need
Obviously a camera and the proper cable: USB for most consumer models and the Eos 1D(s)3, Firewire for the Canon 1D(2) and 1D(s)Mk2(n).
Apart from that, you’ll need some software to connect the camera to the computer and some kind of viewer or raw converter.
The software
There are a few options: Capture One Pro is highly regarded, and does all in one package, but the price is fairly steep.
Then there’s Bibble Pro. Quite a bit cheaper and supports more (older) cameras then C1Pro. Both of these support Nikon and Canon. Bibble also supports other brands. Both are available for Windows and OSX, Bibble also for Linux. Neither allow remote control of the camera, but Capture one allows you to fire the shutter remotely.
Free
Lucky for us that Canon also offers a free solution: Eos Utility. It came on the disk with your camera. If it didn’t, or you lost the disk, you can download it, following the instructions here.
Once installed, you’ll also need a viewer. I prefer to use DPP on my laptop, since that’s a dinosaur an old Powerbook G4 with a 12″ screen. Others prefer to use Lightroom. I’ll explain how to use both:
Step by step
First, start Eos Utility and go to the preferences: (Do this before connecting the camera. On my Mac (OSX 10.4.11) at least, it won’t complete start up, and needs to be force-quit otherwise)
Since I use DPP mostly for tethered shooting, I set up my Folder and filenames to be meaningful here. If you use Lightroom, you can skip this name customization.
The name is pretty self-explanatory I think. I use 3 lines for Year/Month/Date, since the preset “Shooting day” will add a few underscores I don’t want.
Again, pretty obvious naming scheme: My initials, the date and a short description.
Then set DPP as Linked Software.
Now for the shooting
Exit the prefs. That get’s you back to the main window. Choose “Camera Settings / Remote Shooting”
You get this: Note that, unlike other tethering software, Eos Utility gives you complete control over the camera. Very, very nice if the camera is at a position where you can hardly reach it (high on a tripod for instance).
Take a shot. If the “quick preview” window opens, click it away, since you won’t be needing that. It will stay gone as long as you don’t restart Eos Utility.
The image will now automatically open in DPP, in thumbnail view.
That’s not my preferred way of working. So I hit Cmd+A (select all) and Cmd+right arrow (open in edit image window; no shortcut for it on PC). That gives me this:
Cmd+T gets rid of the tools. All consecutive images will open in the edit image window now. At whatever zoom factor you choose.
You’re all set. So shoot away.
Lightroom
In Lightroom it’s a bit more complicated different.
Set everything the same in Eos Utility, except of course the linked software. As said, you also don’t need to worry about folder naming, because that is taken care of in Lightroom:
Then open Lightroom. It will open with the images you last edited / imported. Enable Auto Import, and set up a watched folder like this, in the very logically named “Auto Import Settings”:
Note that your images will get moved (not copied) by LightRoom into the folder you specify here. No way around it, so the whole naming scheme for folders in Eos Utility is kinda redundant in this case. I’d strongly recommend using a meaningful foldername. You can use either LR or Eos Utility to manage the filenames, depending on what you prefer.
Take a shot:
Note the image in the background is still the old image. If after the shot you get “No Photo Selected”, click a thumbnail in LR.
That’s it. Lightroom will now keep an eye on that folder, and import every image that lands in there. A bit slower on my laptop then DPP, but it works okay.
The drawbacks
Tethered shooting causes the battery of your camera to drain faster. With some cameras (the 1D comes to mind) that’s not something you desire…
Obviously, you also need to lug a laptop with you, but IMO that’s well worth it.
Lastly: Eos Utility does not like it when the camera goes to sleep, or is disconnected: It’ll crash. No idea why it’s buggy that way, probably because it’s free.
Tags: Canon, DPP, LightRoom, software
Black and White
Posted by René | Filed under General, Grayscale, software
What do humans see?
The human eye is most sensitive for yellow-green light. Take a look at the next gradient for instance:
To me, indeed the green-to-yellow part looks brightest. Not so to Photoshop however.
About a hundred ways to loose the color
Well, maybe not thàt much, but quite a few anyhow. The easiest way (but offering zero control) would be to go through Image > Mode > Grayscale. That’ll give you this:
Your image just became 1/3 of the original size, and that weight loss is caused because there’s now only a ‘gray’ channel instead of a red, green and blue one.
Big drawback of this method, is that it’s destructive: You indeed loose the color: It’s gone for good. Since you also have zero control, I’d never use this method.
Layers
So, we want something that’s reversible. Lots of ways to do that, using (adjustment) layers, but not all of them good… Let’s start off by naming just about the worst way imaginable: Desaturate. What this does, is that it removes all color information from an image, without the option for any user intervention. While that may or may not be important to you, this should be: All colors are treated as if they were equal.
While equality is a great thing, in this case, it isn’t, since to us different colors aren’t equal.
What does Photoshop see?
Simply put: Numbers. If you’d open the above color gradient in Photoshop, the eye dropper will show you what it’s made of: A simple gradient in each channel. The image below shows the channels:
To understand what Photoshop sees a bit better, have a look at the info palette, and in particular the HSB values there. The only thing changing there is the hue angle! Saturation and Brightness remain at 100 percent in the entire gradient.
Not vastly surprising then, that this is what you get when you do a ’straightforward’ desaturate:
Hue and Saturation are at 0, Brightness is at 50 percent. This might be correct “by the numbers”, but it’s not what I’d want for making a nice black and white image…
A better way
As with most things in Photoshop, there’s plenty of ways to convert a color image to a grayscale. I’m going to show a few here that do a better job then desaturate, and offer more control then ‘Image > Mode > Grayscale’.
One simple way would be to use blend modes: Duplicate the background layer, desaturate the duplicate layer and set the blend mode of the top layer to color.
This can all be done using keyboard shortcuts: Cmd+J, Shift+Cmd+U, Shift+Opt+C, so is very quick.
Disadvantage of that method is that it doubles the file size.
Photoshop is acting more then a bit goofy here by the way: If you desaturate the top layer, you essentially fill it with medium gray. However, if you create a new layer and fill that with medium gray (or black or white or whatever shade of gray in between) by using the fill command, the file size does not double. Very weird indeed.
So the fastest way to go black and white without doubling the file size would be this: Shift+Cmd+Opt+N, Cmd+Backspace, Shift+Opt+C.
Control
All nice and fast, but this doesn’t give you much control. So let’s try a different method. Make a Hue / Saturation adjustment layer. Set saturation to 0. Now you have the uniform gray image of the example above. Now, set the blending mode to ‘Color’ (Or Hue, or Saturation. Doesn’t matter in this case.) Same as when you use that blend mode on a layer filled with pixels! Yet still no control.
To get control, add another hue saturation adjustment layer between this one and the background image. Set the blend mode to ‘Luminosity’. Do not touch the Saturation slider here however. Instead, use the ‘Hue’ slider to alter the grayscale image.
The example below shows the effect of a shift in hue of +40:
Alternatives
As said, in Photoshop there are more ways to do this.
You could for instance just copy the contents of one channel into the image. What works better then that, is to use either the ‘Calculations’ command or, more flexible and a bit easier to understand, a Channel Mixer adjustment layer.
Tick the grayscale box there, and PS will default to these values:
You can then drag any slider to wherever you want, creating the type of black and white image you want. For instance for a portrait, using more red will result in lighter skin tones, using more green will give more contrast… As can be seen in the screenshot, Channel Mixer will warn you when the total of channels goes over 100 percent. However that does not mean that you must never go higher. Depends on the image really… The Histogram is your friend here.
The two gradients made with channel mixer: First default setting, then the altered setting:
Channel mixer has the strangeness that if you untick the ‘Monochrome’ box, the values for all channels stay at what you set (83, 24 and 5 percent in the above example). If however you then tick the ‘Monochrome’ box again, you’re back at the default values! Not the brightest decision Adobe ever made I think.
New to CS3
In PSCS3, Adobe introduced the ‘Black and White’ adjustment layer. It’s quite a bit like a Channel mixer, but is adjustable for 6 colors, instead of 3 channels. So it offers more control (and more options for the user to screw up).
Apparently, someone at Adobe must have been watching Spinal Tap, since the sliders of this adjustment layer range from -200 to +300. ‘Goes to eleven‘ indeed. For the adventurous: There’s also an ‘Auto’ button.
New to CS4
In PSCS4, Adobe included the new ‘Vibrance’ adjustment that was first introduced in Lightroom and ACR. That adjustment also features a ‘Saturation’ slider.
If you use that slider to desaturate an image, it quickly becomes clear that this is working different then the ‘Hue Saturation’ adjustment. You could say it’s actually working nice.
This is whet you get if you drag the Saturation to -100: A contrasty version of what you get using ‘Channel mixer’.
Some tips
If you set any of these adjustment layers to blend mode ‘Color’, you get the exact same result as in the above example with a gray pixel layer set to blend mode ‘Color’: A standard B&W conversion.
This can be useful as a quick way to compare your conversion to a ’standard’ grayscale conversion to see if your version is actually better…
Blend mode ‘Color’ will also work for a ‘Solid Color’, ‘Gradient’, ‘Gradient Map’ or ‘Pattern’ adjustment layer. While I cannot think of a use for ‘Pattern’, the first two work similar to a gray pixel layer set to ‘Color’, while the third offers interesting possibilities. Maybe not what you’d want for your average, day to day grayscale conversion, but nice to experiment a bit.
I leave you with an example of that: A ‘Gradient Map’ adjustment layer, using the preset ‘Copper’, then set blend mode to ‘Color’, on an actual photo:
Tags: Grayscale, PhotoshopCS4, software
Sharpening in Lightroom 2
Posted by René | Filed under General, LightRoom, software
How does it work?
Lightroom 2 has two kinds of sharpening: Capture sharpening and output sharpening. Capture sharpening is used to neutralize the blurring caused by the Anti Aliasing filter in your camera.
Output sharpening is dependent on output (print or screen, what size) and meant to overcome the softening caused by resizing or happening when printing.
Differences
Output sharpening in Lightroom is simple: You get 4 options when you export the image: Off, low, standard or high. All else is taken care of by Lightroom. Ease of use for sure. Drawback is that you cannot preview it, so you’ll need to experiment a bit. After that, it’s “set and forget”.
Capture sharpening on the other hand, requires a bit more user interaction. The settings will depend on camera used, subject and personal preference. You can preview it, but only at 100% or higher magnification. So you either need to zoom in, or you can view sharpening in the microscopic small “preview window” Lightroom 2 has for this purpose.
(There is off course the workaround I mentioned in an earlier blog post)
The “Detail” Tab
…in Lightroom is where it’s at: You get 4 sliders for sharpening: Amount, Radius, Detail and Masking.
Some of these are quite self-explanatory if you know a bit about digital imaging, the others might be new to you. Let’s go over them one by one, using this image:
Notice I have the small “preview” window in the detail tab open. If I didn’t, Lightroom would show an exclamation mark, signifying that “a zoom level of 1:1 or greater is required to see these effects”:
Amount and Radius
These two are pretty obvious: Amount lets you set how much you want to sharpen. Scale goes from “0″ to “150″ (Which is red for a reason: In most cases it will be too much). The default setting is “25″.
Radius lets you set how wide you want the sharpening halos to spread out. Scale goes from 0.5 to 3. Default setting is 1. A higher setting will give you wider sharpening halos.
As with a lot of sliders in Lightroom, you get some “visual help” when you press the Option (Alt) key:
Press Option while sliding the Amount slider, and the image goes grayscale, to better show what the sharpening does to the luminosity values in the image.
Press Option while sliding the Detail slider, and you’ll see just the sharpening halos you are creating.
Detail and Masking
Detail (0 to 100, default 25) suppresses these halos.
A setting of 0 will undo quite a bit of what you did in the above sliders. Again, pressing Option while sliding will give you a fairly accurate idea of how much detail you’re allowing to be sharpened.
Masking does exactly what the name implies: It builds a mask on the fly (which is pretty nifty if you ask me) The default of 0 masks nothing so everything is sharpened, the maximum of 100 will sharpen only the big edges in the image. Press Option while adjusting the slider and, contrary to the other settings above, you’ll be shown the mask, not the effect on the image. Probably Adobe figured that it was less ambiguous that way. (And they were right)
Noise Reduction
… is also present in the Detail tab.
There’s a slider for Luminance NR and one for Color NR.
Color noise consists of randomly colored pixels in an image. Luminance noise is more like “film grain” and less of a problem in my opinion.
That’s good, since in most cases, Color noise is fairly easy removed in Lightroom. Luminance Noise reduction is not. At least, not without loosing detail in the process.
Unfortunately, the Lightroom engineers didn’t provide a “visual aid” for noise reduction, so you’re down to good old WYSIWYG.
Here’s the image again. First without sharpening or noise reduction (notice the “switch” in the top left of the “Detail” tab is in the “off” position):
Next, with sharpening but without Noise Reduction. Pretty big difference.
Let’s see what just Color NR does. Notice the random “blobs of color” that were present in the previous image are about gone. And that with a fairly low setting:
Finally. with both Color and Luminance NR. Notice we are already losing detail in the last, while there’s still Luminance noise present.
Finally, here is the exported image, with “standard” output sharpening for screen:
Hope this has shed some light on the subject of sharpening in Lightroom.
Tags: LightRoom, Preview, printing, WYSIWYG
Clipping Warnings in Lightroom
Posted by René | Filed under Color Management, LightRoom, Problem, software, web
And why they deceive you
Adobe Photoshop Lightroom, like many other Raw converters, has a clipping warning.
The purpose of it is to give you a visual warning (apart from the histogram) of what parts of an image might be clipping.
What is clipping?
A pixel is clipping when it reaches a value of 0 or 255 in one or more channels, and “should have gone further”. Since it cannot go lower then 0 or go higher then 255, it remains at those values: Detail is lost if one or two color channels clip, part of the image is solid black or white if all 3 channels clip.
The effect of color space
As with anything in digital imaging, the color space used has a big influence: A wide gamut color space (such as ProPhotoRGB) will have lower values for the same color then for instance sRGB. So a color that is clipping in sRGB, need not be clipping in ProPhotoRGB!
This color for instance, has sRGB values of (250,40,30). The ProPhotoRGB values are (177,76,36) for the exact same color.
This means that you have a lot more “headroom” in ProPhotoRGB before you hit the “clipping wall”.
So what?
Lightroom uses MelissaRGB internally (ProPhoto RGB with sRGB Tone Response Curve).
The histogram in Lightroom is based on its internal working space. So when you are exporting images for a web gallery, the images might be clipping big time while Lightroom is not warning you!
An example
I opened a DNG file in Lightroom 2.4 and in ACR 5.4. These have basically the same raw conversion engine. The exact same settings were used in both Raw converters.
Here is the image, histogram and clipping warning in Lightroom. (click image to open bigger).
Almost no clipping indicated (It makes no difference what output color space you choose): Just a bit in the lower right that goes almost black, and absolutely no clipping highlights according to Lightroom:
Here is the image in ACR 5.4. Output color space is ProPhotoRGB: About the same clipping warning Lightroom is giving.
Here is the same image in ACR 5.4. Output color space is sRGB: major clipping!
For reference: Here is the image exported out of Lightroom: Clipping indeed:
Workaround
Is there a workaround? No (except using ACR that is).
Simply sad said, the only thing you can do is watch the histogram, guess, and use your eyes. If your screen has close to sRGB gamut, clipping in sRGB might also be visible on screen (as can be seen from the above screenshots in Lightroom).
If you use a wide gamut screen however, you might see quite a difference between the Lightroom “Develop” module and the actual exported image…
Tags: Color Management, LightRoom, Preview, WYSIWYG
